The present invention relates to an ATM-PON system realizing an access network of FTTC/H(fiber-to-the-curb/home), more particularly, to an optical network unit function processing apparatus in ATM-PON system linked directly to a plurality of subscriber""s lines.
xe2x80x9cAn ATM-PON optical subscriber""s transmitting system and a method thereofxe2x80x9d as a prior art of a conventional ONU function processing apparatus in ATM-PON is disclosed in Japanese patent No. 1997-232212(OKI Electric Inc., 1997.8.28).
The above prior art proposes an optical subscriber""s transmitting system comprising a WDM(wavelength division multiplexer) circuit for linking to a network, a PDS9passive double star) cell multi-divisional circuit, a PDS cell generation-division circuit, a subscriber""s circuit for a subscriber""s access, other control circuits, and buffers.
Unfortunately, only providing basic functions such as multi-divisional, ATM-PDS cell generation, etc. to realize an inexpensive optical transmitting system, the prior art fails to satisfy both service functions and quality required for an ONU system of high speed and large capacity.
xe2x80x9cInstant Transfer of Huge Contents on an Optical Subscriber Networkxe2x80x9d providing a subscriber""s processing apparatus which comprises AAL, ATM and PHY functional parts for linking to a network is disclosed as another prior art in Technical Report of IEICE CS96-33 by Tara Yoshikawa. The apparatus includes a variety of CPN(customer premises network) linking parts consisting of DSP, FPGA and the like for linking to a terminal, which is designed to transfer data through a common bus.
However, designed to provide inexpensive net work elements for minimum functions which realize an ONU structure based on a PC construction, the above prior art in the paper fails to satisfy both service functions and quality required newly for an ONU system of high speed and large capacity.
xe2x80x9c600 Mbps 150 Mbps Asymmetric ATM-PDS Transmission Equipment for ATM Video Service and ISDNxe2x80x9d is disclosed in Technical Report of IEICE CS97-29 by Hiroshi Ichibangase. The equipment provides a subscriber""s processing unit comprising an optical signal processing part for accessing to a network, a PDS processing part, an ATM multi-division part, am ATM cell assembly/disassembly part, and a subscriber interface terminal for accessing CATV, image, 1.430 link.
As is the case with other prior arts, the prior art in the above-mentioned paper fails to satisfy both service function and quality required newly for an ONU system of high speed and large capacity since the prior art is designed to provide inexpensive network elements having functions of basic ATM multi division and cell assembly/disassembly for realizing ATM and AAL.
As mentioned in the above explanation, the prior art and the prior papers are constructed with minimum functional parts designed with inexpensive and small scale network elements.
However, an ONU of high speed and large capacity is required as new multi-media services appear lately.
Moreover, required are new additional functions such as QOS(quality of service) buffering for efficient network resource management and supplying high quality services, OAM(operation and management) processing, UPS(usage parameter control) and the like.
Therefore, such functional elements of the prior art and papers fail to realize an ONU of high speed and large capacity for efficient network resource management and supplying high quality services.
Accordingly, the present invention is directed to an optical network unit function processing apparatus in ATM-PON system that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
The object of the present invention is to provide an optical network unit processing apparatus including the minimum functions supplied by the prior art and prior papers, to which a QoS(quality of service) buffering function against 622 Mbps traffic, a real-time OAM(operation and management) processing function by a hardware, and an OPC(usage parameter control) function are added.
Additional features and advantages of the invention will be set forth in the description which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the present invention includes an optical distribution network(ODN) matching part carrying out a function of a physical layer required for connecting an optical network unit (ONU)to an optical distribution network; an ATM processing part exchanging an ATM(asynchronous transfer mode) cell with the optical distribution matching part, the ATM processing part carrying out functions of changing a header of an interactive ATM cell, routing, QoS(quality of service) buffering according to service connecting levels, processing real-time OAM(operation administration and maintenance), and UPC(user parameter control); an AAL1 processing part exchanging an ATM cell with the ATM processing part and executing AAL(ATM adaptation layer)1 processing functions such as segmentation of subscriber lines, reassembly, disposal and generation of a pointer, disposal and generation of an ATM cell, restoration of ARTS(synchronous residual time stamp) clock, and cell delay variation(CDV); and a processor connecting part controlling operational modes of the optical distribution network matching part, the ATM processing part, and the AAL1 processing part and reading operational states thereof, the processor connecting part inserting an OAM cell interactively and extracting the OAM cell outside, the processor connecting part reading and writing an external upward/downward connecting memory for establishment and cancellation of connection.
Preferably, the ATM processing part further includes: an upward UTOPIA input part generating an upward connecting memory address in which an information corresponding to the ATM cell is stored by means of reconstructing a header information of the ATM cell read from the AAL1 processing part; an upward connecting table control part processing a parameter related to an upward OAM and UPC function by reading the parameter from the external upward connecting memory in use of an upward connecting memory address generated from the upward UTOPIA input part, the upward connecting table control part storing a value of the parameter in the upward connecting memory after completion of all processes wherein the value of the parameter needs to be updated; an UPC processing part searching to extract a cell exceeding a traffic rate which is compromised by each virtual connection to an upward traffic generated through the upward UTOPIA input part and the upward connecting table control part; an upward OAM processing part searching to detect generation and cancellation conditions of alarm to the upward traffic and generating an OAM cell corresponding to respective alarming states, the upward OAM processing part calculates and accumulates data related to performance when a PM cell is received; an upward UTOPIA output part transforming the received upward ATM cell data into bits, the upward UTOPIA output part transferring the bits to the optical distribution network matching part; an upward connecting-memory connecting part mediating requirements of respective functioning parts so that each of external upward connecting memory is read and written by the upward UTOPIA input part, the upward connecting-table control part, the UPC processing part, the upward OAM processing part, and the processor connecting part; and an upward test-cell generating part generating an ATM cell of an arbitrary form required by an user at an arbitrary speed in order to test external equipment connected to the optical distribution network matching part with ease.
More preferably, the ATM processing part further includes: an downward UTOPIA input part reading the ATM cell from the optical distribution network matching part and reconstructing a header information of the ATM cell, then the downward UTOPIA input part generating a downward connecting memory address storing an information corresponding to the ATM cell; a downward connecting-table control part reading and processing parameters, which are related to the downward OAM and QOS control functions, from an external downward connecting memory in use of a memory address generated from the downward UTOPIA input part, after completion of the processes, the downward connecting-table control part storing values of the parameters which need to be updated in the downward connecting memory; a downward OAM processing part detecting generation or cancellation condition of the downward traffic and generating an OAM cell corresponding to each alarming state, the downward OAM processing part calculating and accumulating function-related data when a forward or backward PM cell is received; a QOS control part storing the downward traffic in accordance with QOS requirements of respective subscribers in buffers of different levels and scheduling the buffers according to the respective QOS levels for differential services; a downward UTOPIA output part transforming the received upward ATM cell data into bits and transferring the bits to the AAL1 processing part; a downward connecting-memory connecting part mediating requirements of the respective parts so that each external downward connecting memory is read and written by the downward UTOPIA input part the downward connecting-table control part, the downward OAM processing part, and the processor connecting part; a cell memory connecting part mediating requirements of the respective parts wherein each of the external cell memory is read and written by the QOS control part and the processor connecting part; and a downward test-cell generating part generating an ATM cell of an arbitrary form required by an user at an arbitrary speed in order to test external equipments connected to the AAL1 processing part with ease.
Preferably, the AAL1 processing part further includes: an upward AAL processing part preparing ATM cell payloads by means of receiving frame numbers, channel numbers, data, and signal data which are inputted to respective lines of a plurality of subscribers and multiplexing the ATM cell payloads generated from the respective lines in order; an upward ATM processing part generating an ATM cell by adding an ATM header to the ATM cell payload multiplexed by the upward AAL processing part; and an upward UTOPIA connecting part supplying the ATM processing part with the ATM cell generated from the upward ATM processing part through an UTOPIA bus.
More, preferably, the AAL1 processing part further includes: a downward UTOPIA connecting part receiving the ATM cell transferred from the ATM processing part through the UTOPIA bus; a downward ATM processing part removing each of the ATM headers in each of the subscriber lines and extracting an ATM payload information; and a downward AAL processing part searching a damaged ATM cell and a mis-inserted ATM cell out of the ATM payload information extracted from the downward ATM processing part, the downward AAL processing part making compensation.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.